I've never watched One Tree Hill. The thought of it makes my eyes roll, which I fully admit is quite an elitist thing to say coming from someone who endorses Gossip Girl, 90210 and most recently Ringer. But whatever, it just looks generic and uninteresting to me. I did however find this Vulture post particularly helpful/hilarious in explaining everything that has happened in 174 episodes in 3 paragraphs.
It doesn't really touch on just why Laguna Beach's hopelessly stupid Stephen Colletti joined the cast, but finally in their final season premiere they gave us a reason to care. Thanks to Socialite Life for watching and screencapping so we didn't have to.